TWO UNDESCRIBED PELECYPODA — ETHERIDGE. 203 



Group, boring wood, but in this case the valves of the shell were 

 discovered, an advantage I have not possessed. 



Another species, larger than Stoliczka's T. crassula is the huge 

 T. pugetensis, White," from the Puget Group of Western America, 

 probably of uppermost Cretaceous age. This was also found in 

 wood, and although the valves were not seen, every probability 

 exists that it is a true Teredo, closely akin to the Queensland 

 form. The sheath diameter of the two is almost the same. 



In an excellent article on Teredo and its work, by Mr. A. M. 

 Snow,^^ the latter says, speaking of course of the living forms : — 

 "The largest diameter ever noticed by the author measured 1|^ 

 ins. . . . After the Teredo has penetrated the wood for a little 

 distance, the diameter remains about constant." He adds that ,.%' 



a large size indicates a warm climate. .A* 



The Queensland fossil may be known as Teredo vastitas}^ "^ > 



An examination of the wood by means of thin sections prepared 

 for the microscope, has not yielded the satisfactory results expected. 

 In the first place two facts are established — (l)Thewood had clearly 

 undergone long maceration in water previous to fossilisation, pro- 

 ducing a half rotten condition; (2) the trunks also underwent 

 considerable lateral pressure, as evinced by the broken up state 

 of the tissues. The latter are impregnated with iron oxide and 

 some silica. All that I can venture to afiirm at present is the 

 Coniferous nature of the wood, but whether Araucariform or 

 Cupressiniform must remain for future and better material to 

 decide. The evidence obtainable from transverse and tangential 

 sections is sufficiently conclusive on the first point, but the radial 

 sections do not afford sufficient data to warrant the drawing of a 

 hard and fast conclusion on the second. In transverse sections, 

 notwithstanding the disabilities already mentioned, the walls and 

 cavities of the woody fibres are exhibited in regular quadrangular 

 spaces, with a one-inch objective, also the medullary rays and some 

 resin ducts. In tangential sections, the vertical walls and spaces 

 of the woody fibres are quite apparent, and so are the transverse 

 sections of groups of medullary rays, with the parenchymatous 

 cells uniserial and variable in number in the difierent groups, the 

 latter being very abundant. All my radial sections, and many 

 have been made, are a failure from an anatomical point of view 

 for reasons already given ; all that can be distinguished is a mass 

 of badly preserved and crushed woody fibre. So much depends 

 on the radial section in the differentiation of Coniferous woods, 

 that I am afraid I can do no more than suggest that, granting a 

 Coniferous nature, this wood may be either Araucariform or 



U C. A. White— Bull. U.S. Geol. Survey (Powell's), No. 51, 1889, p. 62, pi. 

 viii. 



12 A. M. Snow— Trans. Am. Soc. Civil Engineers, xl., No. 837, 1898, p. 189. 



13 Vastitas, an empty place, waste, or desert, in allusion to the locality. 



